Railway signaling apparatus



April 1943- T. w. TIZZARD; JR 2,317,562 RAILWAY SIGNALING APPARATUS 7 Filed Feb. 25, 1942 bviizvmdmam JZ'zzandJn BY j lbsAz'z'amy.

Patented Apr. 27, 1943 RAILWAY SIGNALING APPARATUS Thomas W. Tizzard, Jr., Downers Grove, 111., assignor to The Union Switch and Signal Company, Swissvale, Pa., a corporation of Pennsyl- Vania Application February 25, 1942, Serial No. 432,217

5 Claims.

My invention relates to railway signaling apparatus, and particularly to apparatus for controlling highway crossing signals located at the intersection of a highway and a stretch of railway track over which trains move in both directions.

It has heretofore been proposed to control the crossing signals by employing a stick relay which is energized when the section including the highway is occupied and which when energized establishes a stick circuit to maintain itself energized as long as the section at one side of the intersection is vacant and the section at the other side of the intersection is occupied. This relay also operates when energized to establish a circuit to supply energy to the crossing signal control relay when the track section which includes the intersection is vacated.

Under normal conditions, therefore, when a train vacates the section beyond an intersection the stick relay is deenergized and the crossing signals are thereafter controlled by the track relays so that operation of the signals will be initiated on the approach of a second or following train.

However, with the arrangement heretofore employed if a second or following train enters the section on one side of an intersection at substantially the same instant that the first train vacates the section on the other side of the intersection, the stick circuit for the stick relay may be reestablished before this relay releases, and if this occurs the relay will remain energized and will prevent operation of the crossing signals to warn of the approach of the second train.

It is an object of this invention to provide improved means of the type described which is arranged so that the equipment is certain to operate to warn users of the highway of the approach of a second or following train.

A further object of the invention is to provide apparatus of the type described which is arranged so that the track relays for the sections on oppo site sides of the intersection control the polarity of the energy supplied to the stick relay so that energy of one polarity is supplied to this relay when one of these track relays is released and the other is picked up, while energy of the other polarity is supplied to this relay when said other track relay is released and said one track relay is picked up. This insures that if the stick circuit for the stick relay is reestablished by a second or following train, as explained above, the polarity of the energy supplied over this circuit will be reversed so the stick relay is certain to release and cause the crossing signals to operate to warn of the approach of the second train.

Another object of the invention is to provide improved means for controlling a stick relay.

In practicing my invention I modify the circuit heretofore known by having the pick-up as well as the stick circuit of the stick relay controlled by contacts of the track relays for the sections on opposite sides of the intersection, while these circuits are controlled in such manner that energy of one polarity is supplied at times and energy of the other polarity is supplied at, other times.

i I shall describe two forms of apparatus embodying my invention and shall then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showing one form of apparatus embodying my invention, and

Fig. 2 is a fragmentary diagram showing a modified form of apparatus which I may employ.

Similar reference characters refer to similar parts in each of the two views.

I Referring to Fig. 1 of the drawing, the reference characters I and 2 designate the track rails of a stretch of railway track over which trafiic moves in both directions. The track rails are divided by insulated joints 3 into relatively long track sections IT and ST which are separated by a relatively short intermediate track section 2T which includes an intersection with a highway H. A crossing signal S is located adjacent the intersection to warn users of the highway of the approach of a train. The signal S may be of any appropriate form and as here shown is an audible signal in the form of an electric bell.

Each of the track sections is provided with a track circuit including a track battery connected across the section rails at one end of the section and a track relay, designated TR with an appropriate prefix, connected across the section rails at the other end of the section.

The crossing signal S is controlled by a control relay XR, while the relay R is controlled by the track relays and by an auxiliary or stick relay XS.

The equipment is shown in the condition which it assumes when the track stretch is vacant. At this time the track relays are picked up and energy is supplied to the relay XR by a circuit which includes front contact I 0 of relay ITR, from contact II of relay 3TR, and front contact I 2 of relay 2TB.

The energy supplied to relayXR, as well as t the relay XS and the crossing signal S, may be supplied from a suitable source, such as a storage battery or a primary battery, not shown, the positive and negative terminals of which are designated B and C, respectively.

As relay XR is energized its contact I i is picked up and interrupts the circuit of the crossing signal S so that this signal is prevented from operating.

When a train moving from left to right enters section IT track relay I TR releases and its contact III interrupts the circuit of the relay XR. so that its contact I4 releases and establishes the circuit of crossing signal S which then operates to warn users of the highway of the approach of a train.

When the train advances into section 2T track relay 2TB releases and its contact I2 additionally interrupts the circuit of the relay XR, while contact I5 of relay 2TB establishes a pickup circuit for the stick relay XS. This circuit is traced from terminal B through back contact I5 of relay 2TB, back contact I6 of relay ITR, winding of relay XS, front contact I8 of relay 3TH, and back contact I9 of relay ITR to terminal C.

When the train advances into section 3T track relay 3TH releases and its contact I8 interrupts the circuit traced above so that relay XS releases, while contact I I of relay 3TB additionally interrupts the circuit of relay XR.

When the rear of the train vacates section IT track relay ITR picks up and establishes a pickup circuit for relay XS which is traced from terminal B through back contact I5 of relay 2TB, front contact I5 of relay ITR, back contact I8 of relay 3TH, winding of relay XS, and front contact I 9 of relay ITR to terminal C. The relay XS therefore picks up and its contact establishes connection from terminal B to contact I6 of relay ITR so that relay XS will continue to be energized after the train vacates section 2T.

In addition, on picking up of relay XS its contact 22 establishes a connection to supply energy to relay XR after the train vacates section 2T. Accordingly, when the train vacates section ET and track relay 2TB. picks up its contact I5 interrupts the pick-up circuit for relay XS, but this relay is held picked up by energy supplied over its stick circuit, while contact I2 of relay 2TB is closed so that energy is supplied to relay XR over the circuit established by contact 22 of relay XS. Relay XR, therefore, picks up and discontinues operation of the crossing signal S.

When the train advances far enough to vacate section 3T track relay 3TB picks up and its contact II completes one circuit for supplying energy to the relay XR, while its contact I3 interrupts the stick circuit for relay XS so relay XS releases and its contact 22 interrupts the circuit which it controls for supplying energy to relay XR. However, at this time relay XR is maintained picked up by current supplied over the contacts of the track relays and relay XR, therefore, remains picked up and prevents operation of the crossin signal.

The system of this invention is arranged so that if a second or following train enters section IT before the first train vacates section 3T the crossing signal S will operate to warn of the approach of the second train.

As explained above, when the first train vacates section 2T track relay 2TB picks up and energy is supplied to relay XR over the circuit which includes front contact 22 of relay XS, while relay XS is energized by current supplied over the stick circuit which includes its own front contact 29, front contact Iii of relay ITR, back contact I8 (iii of relay 3TB, winding of relay XS, and front contact I9 of relay ITR.

When the second or following train enters section IT track relay ITR releases and its contact I6 interrupts connection through back contact I8 of relay 3TR to one terminal of the winding of relay XS so that relay XS releases and its contact 22 cuts off the supply of energy to relay XR with the result that contact I4 establishes the circuit to supply energy to the signal S to thereby cause the signal to operate and warn users of the highway of the approach of the second train.

The system of this invention is also arranged to insure release of the relay XR and resultant operation of the crossing signal S if a second train enters section IT at substantially the same instant that the first train vacates section 3T so that relay ITR releases and relay 3TB picks up approximately at the same time.

On release of the contacts of relay I TR or picking up of the contacts of relay 3TB, whichever occurs first, the stick circuit for relay XS is interrupted and after a short time interval contact 20 of relay XS will release and prevent reestablishment of the relay stick circuit by contacts of relays ITR and 3TR. However, if the contacts of relay ITR- release and the contacts of relay 3TR pick up before the contacts of relay XS release, a circuit for supplying energy to the relay XS will be complete and is traced from terminal B through front contact 20 of relay XS, back coritact I6 of relay ITR, winding of relay XS, front contact I8 of relay 3TB, and back contact I9 of relay ITR. to terminal C. It will be seen that energy supplied over this circuit flows through the winding of relay XS in the opposite direction to that previously supplied to the relay, and when the flux in the relay core passes through the zero value the contacts of relay XS release and contact 20 interrupts th relay stick circuit so that the relay contacts remain released, while contact 22 of relay XS interrupts the circuit of relay XR and causes it to initiate operation of the crossing signal S. As there is a reversal of the polarity of the energy supplied to the relay XS at this time the relay is certain to release and cause'the crossing signal to operate.

The system of this invention operates in a similar manner on movement of trains through the track stretch from right to left. When a train moving in this direction enters section 3T track relay 3TR releases and its contact I I interrupts the circuit of relay XR and this relay causes signal S to operate.

When the train enters section 2T track relay ZTR releases and its contact I2 additionally interrupts the circuit of relay XR, while its contact I 5 establishes a pick-up circuit for relay XS. This circuit is traced from terminal B through back contact I5 of relay 2TB, front contact I6 of relay I TR, back contact I8 of relay 3TB, winding of relay XS, and front contact I9 of relay ITR to terminal C.

When the train enters section IT track relay ITR releases and its contact l6 interruptsthe circuit traced above for energizing relay XS while its contact I0 additionally interrupts the circuit of relay XR,.

When the train vacates section 31 track relay 3TH, picks up and establishes a pick-up circuit for relay XS which is traced from terminal B through back contact I5 of relay ZTR, back contact I6 of relay ITR, winding of relay XS, front contact I8 of relay 3TR, and back contact IQ of relay ITR to terminal C. The relay XS, therefore, picks up and its contact 20 establishes connection from terminal B to contact I6 of relay ITR to maintain the relay XS energized after the train vacates section 2T.

When the train vacates section 2T track relay 2TB, picks up and interrupts the pick-up circuit for relay XS but this relay is maintained picked up by energy supplied over its stick circuit. When relay 2TB picks up energy is supplied to relay XR over the circuit including front contact 22 of relay XS, and front contact I2 of relay 2TB, and contact I4 of relay XR picks up to discontinue operation of the crossing signal S.

When the train vacates section IT track relay ITR picks up and interrupts the stick circuit for relay XS and the contacts of this relay release, while relay XR is maintained energized by cur-- rent supplied over the front contacts of the track relays.

The system of this invention is arranged so that if a second or following train enters section 3T before the first train vacates section IT, the crossing signal S will operate to warn of the ap proach of the second train.

As pointed out above, after the first train vacates section 2T, and while it is still in section IT the relay XS is'energized by current supplied over a stick circuit which includes front contact I8 of relay STR. When a second or following train enters section 3T, track relay 3TB releases and its contact I8 interrupts the stick circuit for relay XS so that relay XS releases and its contact 22 interrupts the circuit of relay XR so that relay XR, releases and causes the crossing signal S to operate, while contact 29 of the relay XS additionally interrupts the stick circuit for relay XS.

The system of this invention is also arranged so that if a second or following train moving from right to left enters section 3T substantially at the instant the first train vacates section IT the relay XS will be certain to release and initiate operation of the crossing signal S to warn of the approach of the second train.

As previously pointed out when a train moving from right to left has vacated section 2T but is still present in section IT, the relay XS is maintained energized by current supplied over the stick circuit which is traced from terminal B through front contact 20 of relay XS, back contact I6 of relay ITR, winding of relay XS, front contact I8 of relay 3TB, and back contact I9 of relay ITR to terminal C.

When the first train vacates section IT track relay ITR picks up and interrupts the stick cir- Y cuit just traced, while when the second train enters section 3T track relay 3TB. releases and additionally interrupts the stick circuit traced above. However, if relay ITR picks up and relay 3TB releases before the contacts of relay XS release another circuit is established for supplying energy to relay XS and is traced from terminal B through front contact 26 of relay XS, front contact I3 of relay ITR, back contact I8 of relay 3TR, winding of relay XS, and front contact I9 of relay ITR to terminal C. The energy supplied over this circuit to the relay XS flows through the relay winding in the opposite direction to that of the energy previously supplied to the winding. The contacts of relay XS therefore will release and its contact 20 will interrupt the circuit just traced to thereby insure that the relay contacts will remain released, while its contact 22 interrupts the circuit of relay XR to cause operation of the crossing signal S.

As the second train proceeds through the track stretch the equipment operates as previ usly explained to continue operation of the crossing signal until the train vacates section 2T.

From the foregoing it will be seen that this invention provides improved means to control the supply of energy to the relay XS in such manner as to insure that this relay willnot prevent operation of the crossing signals when a second train approaches the crossing.

In Fig. 2 of the drawing there is shown a modified means which I may employ to control the stick relay XS. Except as hereinafter pointed out in detail the modification shown in Fig. 2 is the same in construction and operation as the modification shown in Fig. l.

The equipment is shown in the condition which it assumes when the track stretch is vacant. At this time the track relays are picked up and their contacts establish a circuit to supply energy to the relay XR, while relay XS is released.

When a train moving from left to right enters section IT track relay ITR releases and its contact IIJ interrupts the circuit of relay XR to initiate operation of the crossing signal, while when the train enters section 2T track relay 2TB releases and additionally interrupts the circuit of relay XR. On release of relay Z'IR its contact 25 completes a pickup circuit for relay XS which is traced from terminal B of a source through back contact 25 of relay 2TB, front contact 26 of relay 3TB, winding of relay XS, and back contact 24 of relay [TR to terminal C. At this time the contacts of relay XS pick up but the circuit of relay XR continues to be interrupted by contact I2 of relay 2TH.

When the train advances into section 3T track relay 3TB releases and its contact 26 interrupts the circuit just traced for relay XS and the contacts of this relay release. When the train vacates section IT track relay ITR picks up and completes a circuit to energize relay XS. This circuit is traced from terminal B through back contact 25 of relay 2TB, ront contact 24 of relay ITR, winding of relay XS, and back contact 26 of relay 3TB. The contacts of relay XS therefore pick up and-its contact 2! establishes a stick circuit to keep the relay energized after the train vacates section 2'1 and track relay ZTR picks up. When the train vacates section 2T track relay 2TB picks up and energy is supplied to relay XR over the circuit which includes front contact 22 of relay XS and front contact I2 of relay ZTR. The relay XR therefore picks up and discontinues operation of the crossing signal.

When the train vacates section 3T track relay 3TB, picks up and its contact 26 interrupts the circuit of relay XS so that it releases, while contact II of relay 3TB completes the circuit of relay XR so that relay XR remains energized and prevents operation of the crossing signal after relay XS releases.

If before the first train vacates section 3T a second or following train enters section IT the track relay ITR will release and interrupt the stick circuit for relay XS so that it will release and deenergize relay XR to thereby cause the crossing signal to operate to warn users of the highway of the approach of the second train.

If the second train enters section iT at substantially the same instant that the first train vacates section 3T energy will be supplied to relay XS over the circuit which includes front contact 2? of relay XS, front contact 26 of relay 3TB, winding of relay XS, and back contact 24 of relay |1TR.. The. energy supplied over this circuit, flows through the winding of relay XS in the. direction opposite to the energy supplied, to relay: XS when relay ITR is picked up and. relay 3TB is released. Accordingly relay X8 is certain to release so that its contact 21 interrupts the circuit just traced to thereby prevent picking up of the relay, while its contact 22 interrupts the supply of energy to relay XR. and thus causes operation of the crossing signal.

The equipment operates in a similar manner on movement of a train through the track stretch from right to left. When such, a train enters section 3T track relay 3TH releases and releases relay XR to thereby initiate operation of the crossing signal. When the train enters section 2T track relay 2TB releases and additionally interrupts the circuit of relay XR. At this time relay XS picks up but as soon as the train enters section IT the circuit of relay X8. is interrupted and relay XS releases. When the train vacates section 3T relay XS is picked up by current supplied over terminal B through back contact 25 of relay 2TH, front contact 26 of relay 3TB, wind, ing of relay XS, and back contact 24 of relay VIP- to terminal C. On picking up of relay XS its contact 2'! establishes a stick circuit to keep the relay energized after picking up of relay 2TR- while when the train vacates section 2T energy is supplied to relay XR over front contact 22 of relay XS and front contact l2 of relay ZTR so that operation of the crossing signal is discontinued.

If a second or following train enters section 3T before the first train has vacated section IT contact 26 of relay 3TB will interrupt the circuit traced above for energizing relay XS and this relay will release and interrupt the circuit of relay XR and thus caus the crossing signal to operate to warn of the approach of the second or following train.

The system shown in Fig. 2 also operates to insure release of relay XS if a second train enters section 3T substantially at the same in stant that the first train vacates section 1T. When section IT is vacated and section 3T is occupied energy may be supplied to relay XS over the circuit which is traced from terminal B through front contact 21 of relay XS, front contact 24 of relay ITR, winding of relay X8, and back contact 26 of relay 3TH to terminal C. The energy supplied over this circuit flows through the relay XS in the direction opposite to that of the energy supplied to the relay when section IT is occupied and section ST is vacant. Accordingly the relay is certain to release and initiate operation of the crossing signal to warn of the approach of the second train.

Although the equipment has been illustrated and described in connection with the control of highway crossing signals the invention is not limited to use for this purpose, but is equally applicable to other situations.

Although I have herein shown and described only two forms of railway signaling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track over which trafiic moves in both directions, said track stretch being divided into a first and a second track section which are separated by an intermediate section which; includes; a h ghw y intersection, each, o said tralQk" sections bei g pr vided with a track circuitincluding a track relay, a highway crossing signal located at said intersection a, control relay effective when energized to; interruptv the circuit, of said signal, a circuit including front, contacts of each of said track relays for supplying energy to said control relay, an auxiliary re1-ay, a circuit including front contacts of th intermediate section track relay and of said auxiliary relay for also supplying energy to said controlrelay; a pick-up circuit for said auxiliary relay including a back contact of the intermediate section track relay, a stick circuit for said, auxiliary relay including its own front contact, and means including contacts of the first and second section track relays for controlling the circuits of said auxiliary relay so that when the contacts of the first section track relay are picked up and th contacts ofthe second section track relay are released energy of one polarity is supplied to said auxiliary relay and so that when the contacts: of the first section track relay are released and the contacts of the second section track relay are picked up energy of the other polarity is supplied to said auxiliary relay.

2. In combination, a stretch ofrailway track over which traific moves in both directions, said track stretch being divided into a first and asecond track section which are separated by an intermediate section which includes a highway intersection, each of said track sections being provided with a track circuit including a track relay, a highway crossing signal located at said intersection, a control relay efiective when energized to interrupt the circuit of said signal, a circuit including front contacts of each of said track relays for supplying energy to said control relay, an auxiliary relay, a circuit including front contacts of the intermediate section track relay and of said auxiliary relay for also supplying energy to said control relay, means including a back contact of the intermediate section track relay for establishing connection from one terminal of a source to a contact of said first section track relay which is eiiective when released to establish connection with one terminal of the auxiliary relay winding and is efiective when picked up to establish connection with the other terminal of the auxiliary relay winding providing the contacts of the second section track relay are released, means including a front contact of said auxiliary relay for also establishing connection from said on terminal of said source to said first section track relay contact, and means including another contact or the first section track relay for establishing connection from the other terminal of said source to said one terminal of the auxiliary relay winding when said contact is picked up and to the other terminal of the auxiliary relay winding when said contact is released provided the contacts of said second section trac relay are picked up.

3. In combination, a stretch of railway track over which traific moves in both directions, said track stretch being divided into a. first and a second track section which are separated by an intermediate section which includes a highway intersection, each of said track sections being provided with a track circuit including a track relay, a highway crossing signal located at said intersection, a control relay effective when energized to interrupt the circuit of said signal, a

circuit including front contacts of each of said track relays for supplying energy to said control relay, an auxiliary relay, a circuit including front contacts of the intermediate section track relay and of said auxiliary relay for also supplying energy to said control relay, one terminal of the winding of said auxiliary relay being connected to a contact of the first section track relay which when released establishe connection with one terminal of a source and is effective when picked up to establish connection with the other terminal of said source provided the second section track relay is released or the auxiliary relay contacts are picked up, the other terminal of the winding of said auxiliary relay being connected to a contact of the third section track relay which is effective when released to establish connection with said one terminal of said source and is efiective when picked up to establish connection with said other terminal of said source provided the second section track relay is released or the auxiliary relay contacts are picked up.

4. In combination, a stretch of railway track over which trairic moves in both directions, said track stretch being divided into a first and a second track section which are separated by an intermediate section, each of said sections being provided with a track circuit including a track relay, an auxiliary relay, a pick-up circuit for said auxiliary relay which includes back contacts of the track relays of the first and intermediate sections and a front contact of the track relay of the second section and over which energy of one polarity is supplied to said auxiliary relay, another pick-up circuit for said auxiliary relay including back contacts of the track relays of the second and intermediate sections and a front contact of the track relay of the first section and over which energy of the other polarity is supplied to said auxiliary relay, and means including a front contact of said auxiliary relay and shunting the contact of said intermediate section track relay in each of said pickup circuits.

5. In combination, a stretch of railway track over which traffic moves in both directions, said track stretch being divided into a first and a second track section which are separated by an intermediate section, each of said sections being provided with a track circuit including a track relay, an auxiliary relay, a pick-up circuit for said auxiliary relay which includes back contacts of the track relays of the first and intermediate sections and a front contact of the track relay of the second section and over which energy of one polarity is supplied to said auxiliary relay, another pickup circuit for said auxiliary relay including back contacts of the track relays of the second and intermediate sections and a front contact of the track relay of the first section and over which energy of the other polarity is supplied to said auxiliary relay, and means including a front contact of said auxiliary relay and shunting the contact of said intermediate section track relay in each of said pick-up circuits, a control relay, a circuit including front contacts of each of said track relays for supplying energy to said control relay, and a circuit including front contacts of said intermediate section track relay and of said auxiliary relay for also supplying energy to said control relay.

THOMAS W. TIZZARD, JR. 

